And the answer is… (drum roll, please)

Riddle 3

 

Yes, the first figure represents two doorposts and the lintel marked with blood of Passover sacrifice and circumcisions as is says:

 וְלָקְחוּ, מִן-הַדָּם, וְנָתְנוּ עַל-שְׁתֵּי הַמְּזוּזֹת, וְעַל-הַמַּשְׁקוֹף–עַל, הַבָּתִּים, אֲשֶׁר-יֹאכְלוּ אֹתוֹ, בָּהֶם

And they shall take of the blood, and put it on the two side-posts and on the lintel, upon the houses wherein they shall eat it. (Ex. 12:7)

The second picture is of the splitting of the sea, as it says:

 וַיָּבֹאוּ בְנֵי-יִשְׂרָאֵל בְּתוֹךְ הַיָּם, בַּיַּבָּשָׁה; וְהַמַּיִם לָהֶם חוֹמָה, מִימִינָם וּמִשְּׂמֹאלָם

And the children of Israel went into the midst of the sea upon the dry ground; and the waters were a wall unto them on their right hand, and on their left. (Ex. 14:22)

And both have to do with time. But this is a subject for another post.